Structural and phase evolution in U3Si2 during steam corrosion
journal contribution
posted on 2024-11-17, 16:24authored byJiatu Liu, Patrick A Burr, Joshua T White, Vanessa K Peterson, Pranesh Dayal, Christopher Baldwin, Deborah Wakeham, Daniel J Gregg, Elizabeth S Sooby, Edward G Obbard
U3Si2 nuclear fuel is corroded in deuterated steam with in situ neutron diffraction. Density functional theory is coupled with rigorous thermodynamic description of the hydride including gas/solid entropy contributions. H absorbs in the 2b interstitial site of U3Si2Hx and moves to 8j for x ≥ 0.5. Hydriding forces lattice expansion and change in a/c ratio linked to site preference. Rietveld refinement tracks the corrosion reactions at 350–500 °C and preference for the 8j site. Above 375 °C, formation of UO2, U3Si5 and USi3 take place in the grain boundaries and bulk. Hydriding occurs in bulk and precedes other reactions.